Carotenoids Flashcards
Examples of Provitamin A carotenoids:
a-carotene
B-carotene
g-carotene
B-cryptoxanthin
examples of Non provitaminA carotenoids
lycopene
lutein
zeanthin
astraxanthin
B-carotene characteristics
red-orang pigment
lipid soluble
can be converted to Vitamin A
sources of B-carotene
orange and yellow bright f and v
green leafy V
Lycopene characteristics
red pigment
lipid soluble
no vitamin A activity
Sources of lycopene
tomatoes!! watermelon grapefruit papaya guava apricot
lutein and zeaxanthin characteristics
yellow pigment
lipid soluble
no vitamin A activity
sources of lutein
green veggies - broccoli kiwi corn eggs
sources of zeaxanthin
peppers (yellow and orange) corn potato eggs
bioavailability of carotenoids
cooked and heated processed foods have increased absorption of carotenoids
what must happen in order for dietary carotenoids to be absorbed intestinally?
they must be released from the food matrix and incorporated into micelles
carotenoids absorption requires the presence of ___ in a meal
FAT
where and how are carotenoids absorbed
duod and jejun -
low [] = carotenoid transporters
high [] = passive diffusion
B-carotene can be metabolized in the enterocyte to form _____
retinol
the process of b-carotene metabolism into retinol depends on what
the amount and form of carotenoids consumed and the vitamin A status
carotenoids are transported in ______ to what___
chylomicrons to extra hepatic tissue - (remaining is brought to LV for storage)
carotenoids can be packaged for further transport as part of ____
VLDL or other lipoproteins - then taken back to extra hepatic tissue
where is B- carotene primarily stored
Liver and adipose tissue
where are lutein and zeaxanthin primarily stored
in the macular region of the retina ( because they both freely cross the BBB)
what is the only essental function of B-caroten
source of vitamin A
what other function do B-carotene and other carotenoids have
antioxidant
in light filtering, carotenoids allow what
absorption of light in the visible range of spectrum
what color light do lutein and zeaxanthin primarily absorb
blue
carotenoids are metabolized to a variety of compounds and excreted into ___
bile
vitamin A deficiency may occur in people whose diet is low in both ___ + ___
vitamin A and B-carotene
there is an increased risk of what type of cancer in vitamin A deficiency
prostate
there is an increase risk of age-related macular degeneration with vitamin A (deficiency or toxicity)
deficiency
synthetic B-carotene is in what form
all-trans B carotene
natural B carotene is derived from what
algae
natural lycopene is available from what
tomato
do carotenoids or vitamin A have less toxicity
carotenoids
hypercarotenosis and carotenodermia is what?
yellow-orange discoloration of the skin due to carotenoid toxcity
______ supplementation has been shown to increase the risk of lung cancer in smokers and should be avoided in current smokers
B-carotene
are carotenoids OK in pregnancy
yes- but it is still a good idea to avoid them and high doses alltogether
